Steering wheel for vehicles

ABSTRACT

A steering wheel for vehicles, comprising a steering wheel rim to which is firmly connected a steering wheel hub which is arranged for attaching the steering wheel to the upper portion of a steering shaft installed in a vehicle, the steering wheel hub mainly comprising a spoke hub and an inner hub which are concentric and engage with each other, being mutually displaceable in an axial direction. The spoke hub is firmly connected to the steering wheel rim, and the inner hub is intended to be rigidly mounted on the steering shaft. The spoke hub and the inner hub are connected to each other via a locking means which locks the respective hubs radially and allows mutual axial adjustment of the hubs, whereby the steering wheel can be caused to assume alternative positions in height relative to the steering shaft.

STEERING WHEEL FOR VEHICLES

The present invention relates to a steering wheel for vehicles,comprising a steering wheel rim with a steering wheel hub firmlyconnected thereto and arranged for mounting the steering wheel to theupper portion of a steering shaft installed in a vehicle.

In motor engineering, demands for increased comfort and improvedergonometric conditions for vehicle drivers have been accentuated inrecent times. By making it possible for drivers of vehicles to assumecomfortable driving postures, the risk of fatigue is reduced which inturn results in that traffic safety is improved.

Considering that drivers have different bodily constitutions, it isnecessary for the driving position in a vehicle to be adjustable so thatevery driver can assume his own suitable driving posture. In respect tothis consideration it is known to provide adjustability of the drivingposition by arranging the driver's seat adjustable in differentpositions. Driver's seats and their adjusting mechanisms are generallydimensioned after a statistically normally built person, but in realitythere are very few people conforming to this ideal person.

To increase the adjustability of the driving position in a vehicle, itis also known to provide adjustment of the steering wheel height and/orinclination. Devices for accomplishing this, known up to now, arehowever complicated, and this has resulted in the limited application ofsuch adjusting means in vehicles, and then usually at comparatively highcost.

The height adjustability of the steering wheel in known adjusting meansis usually provided by forming the steering shaft with at least twocoacting parts which are non-rotatably connected and axiallydisplaceable relative to each other. Locking the steering shaft in anaxial position is done in this case by means of a keyed joint, which isplaced between the two displaceable steering shaft portions, or by meansof some form of positive lock.

Telescopic steering shafts require, however, that they are manufacturedwith very severe demands on tolerances so that clearances and play willnot be too large. Also, there are great demands on the mounting means ofthe telescopic parts. These manufacturing demands result in that a meansfor height adjustment of a steering wheel using axial adjustment of atelescopic steering shaft becomes both complicated and expensive tomanufacture.

The present invention has the object of enabling fitting and heightadjustment of a steering wheel to a steering shaft fitted to a vehicle,using a simple and cheap structure, the invention being substantiallydistinguished in that the steering wheel hub comprises at least twoconcentric hub parts with one hub part slidably mounted in another hubpart, and that said hub parts comprise a spoke hub firmly attached tothe steering wheel rim via a plurality of spokes, and an inner hubintended for being rigidly mounted to the steering shaft, said hub partsbeing connected to each other via a locking means positionally fixingsaid hub parts radially and allowing adjustment of said hub parts indifferent axial positions relative to each other.

The steering wheel in accordance with the present invention allows rapidheight adjustment of a steering wheel position, and the adjustmentmechanism is so formed that steering ability and operational safety arenot affected by the varying positions in height of the steering wheel.

Other characterizing features of the invention are apparent from theappended patent claims and can also be read from the description belowof an embodiment exemplifying the invention. The description is madewith reference to the attached drawings, on which

FIG. 1 is a partial plan view of an inventive steering wheel,

FIG. 2 is an axial section along the line II--II in FIG. 1 of thesteering wheel fitted to a steering shaft, and

FIG. 3 shows in the same way an axial section along the line III--III inFIG. 1.

FIGS. 2 and 3 illustrate how a steering wheel 1, intended for steering avehicle, is fitted to a steering shaft 2. The latter is conventionally,rotatably mounted in mounting means (not shown) attached by brackets orthe like to structural portions of the vehicle, e.g. cowling and/orinstrument panel. At its lower end, the steering shaft 2 isconventionally connected to a steering gear (not shown) and/or othermeans included in the vehicle steering system.

The steering shaft 2 is a solid steel shaft of substantially cylindricalshape, and at its upper end it is formed with three shouldered shaftportions 4,5,6 having diameters decreasing successively towards theupper end 3 of the steering shaft. The innermost shaft portion 6 taperstowards the outmost end 3 of the steering shaft, the intermediate shaftportion 5 has splines 7, and the outmost shaft portion 4 is threaded.

The steering wheel 1 is removably attached to the upper portion of thesteering shaft 2, and mainly comprises a steering wheel hub 8 with asteering wheel rim 9, these two being rigidly attached to each other bymeans of a plurality of spokes 10. In its turn, the steering wheel hub 8comprises three concentric hub parts, an inner hub 11, a spoke hub 12and a bottom cap 13. The inner hub 11 is formed to advantage fromaluminium and has a cylindrical outer shape. The inner hub 11 is axiallyformed with an eccentric throughhole 14, the inner surface of which isformed for coaction with the shaft portions 4,5,6 on the upper part ofthe steering shaft 2. The through-hole 14 is thus formed with a taperingportion 16 for coaction with the conical shaft portion 6 on the steeringshaft 2, a portion with splines 15 for coaction with the splines 7 onthe steering shaft 2, while the remaining portion 17 of the through-hole14 is cylindrical and is a free fit on the cylindrical portion of thesteering shaft 2.

When mounting the steering wheel 1 on the steering shaft 2, the conicalsurface 16 of the inner hub 11 is seated against the conical surface 6of the steering shaft 2, and the splines 7, 15 of the inner hub 11 andthe steering shaft 2, respectively, are caused to mesh with each other.The inner hub 11 is then locked axially and radially by a lock nut 56screwed onto the outer portion 4 of the steering shaft 2.

A recess 18 is made in the inner hub 11, parallel to the axis of thethrough-hole 14. An axially extending slot 20 is formed between therecess 18 and the circumference 19 of the inner hub 11. In an axiallymiddle portion the respective sides 22 of the slot 20 are mutuallytapering such that the greatest distance between them is nearest themouth of the recess 18, while the respective sides 25 of the slot 20located in an upper and in a lower longitudinal portion of the inner hub11 are parallel and have a width between them greater than said greatestdistance at the wedged middle portion.

The spoke hub 12 is slideably mounted on the inner hub 11, describedabove. The upper portion of the spoke hub 12 is provided with foursleeve-like attachments 30 into which are pressed the inner ends of thespokes 10. For the major portion of its length, the spoke hub 12 isformed as a cylindrical tube having a radially projecting and axiallyextending projection 26. The latter is formed with an outer planesurface 28, parallel to the central axis of the spoke hub 12. On itsinside, the projection 26 is formed with an elongate inner cavity with aflat bottom 27, parallel to the surface 28 of the projection 26. Betweensaid surfaces 27,28 there is an elongate slot 29 having a limited axialextension.

The lower portion 31 of the spoke hub 12 has a smaller diameter than theupper portion 32 of the spoke hub 12, and the junction between saidportions is formed as a shoulder. As will be seen from the descriptionlater, the surface 33 of the shoulder thus formed constitutes a springseating when the steering wheel 1 is fitted to the steering shaft 2.

The steering wheel 1 is conventionally provided with an outer covering34 of a plastics material, moulded to enclose the spoke hub 12, spokes10 and steering wheel rim 9. In the central portion of the steeringwheel 1, the outer covering 34 is formed with a recess 35, in the upperportion of which a switch 36 is fitted for the vehicle horn, and isfitted by a snap lock. The switch 36 is intended to function in a knownway when pressed axially. For this reason, the switch 36 is connected toa signal horn (not shown) via a wire 37, and via another wire it isconnected to the vehicle earth or ground, which in the example describedhere is illustrated by a connection 57 to the inner hub 11.

The bottom cap 13 is concentrically fitted to the lower portion of theinner hub 11, and is formed with two axial spring tongues 40, disposedfor snapping onto corresponding abutments 41 when the bottom cap 13 isfitted to the inner hub 11. The attachment proper of the bottom cap 13is made with a plurality of screws 38, engaging in axial, threaded holes39 in the inner hub 11. A compression spring 44 is compressed betweenthe inside of the bottom cap 13 and the shoulder surface 33 of the spokehub 12, to actuate the spoke hub 12 upwardly relative to the inner hub11 and the bottom cap 13.

A cranked arm 43 projects out from the lower portion of the bottom cap13, said arm being intended for actuating conventional means resettingthe direction indicators (not shown) of the vehicle to a neutralposition after use. The bottom cap 13 is also provided with an axialsupporting pillar 42 which runs through the axial recess 18 in the innerhub 11 when the bottom cap 13 is fitted to the inner hub 11. A wedge 45is fitted in said recess 18. The former is formed with two rectangularflank portions 47,48 with a wedge shaped portion 46 between them, whichis arranged to fit in the intermediate portion of the axial slot 20 onthe inner hub 11, while the respective flank portion 47,48 of the wedgefits the respective end portion of the axial slot 20, and as previouslymentioned, these end portions are formed with parallel sides 25 oneither side of the intermediate portion formed with sloping sides. Bysuch configuration, the wedge 45 will be axially secured when fittedinto the axial slot 20 on the inner hub 11.

In the intermediate portion 46, the wedge 45 is provided with atransverse hole for a bolt 49. A countersunk portion of the hole isformed to the same configuration as the head 50 of the bolt to lock thelatter against rotation. The shank of the bolt 49 goes through the axialslot 29 in the projection 26 of the spoke hub 12, and at its free end itis provided with a threaded on locking knob 52. The latter comprises athreaded insert 53 and an outer covering 54 of a plastics material. Whenthe knob 52 is tightened down onto the outer, flat surface 28 on eitherside of the axial slot 29 of the spoke hub 12, the intermediate portion46 of the wedge 45 will be pressed into the intermediate portion 22 ofthe axial slot 20 in the inner hub 11, the spoke hub 12 thereby beingclamped ridigly in an axial position relative to the inner hub 11. Thisresults in that the diameter of at least the outer portion of the innerhub 11 increases somewhat, thereby causing the inner hub 11 to beclamped against the interior mantle surface of the spoke hub 12.Furthermore, the locking knob 52 acts as a clamping means per se, sinceit forces the spoke hub 12 inwards, towards the inner hub 11.

The clamping connection between the spoke hub 12 and the inner hub 11described above signifies that the steering wheel rim 9 and the spokehub 12 firmly attached to it are mounted infinitely axially displaceableon the inner hub 11. Furthermore, the shank of the bolt 49 passingthrough the axial slot 20 in the inner hub 11 and the axial slot 29 inthe spoke hub 12 result in that the two hubs 11, 12 are non-rotatablyattached to each other, even if the locking knob 52 is not tighteneddown.

In the inventive height adjusting mechanism, the inner hub 11 and theremovably mounted wedge 45 are consequently positionally fixed relativeto the steering shaft 2, whereas the steering wheel rim 9 and the spokehub 12 firmly connected thereto are displaceable to different axialpositions. For a desired alteration in the axial position of thesteering wheel rim 9, the locking knob 52 is first undone, whereon thespoke hub 12 will be freely movable axially relative to the inner hub11. The shank of the bolt 49 runs freely in the axial slot 29 in thespoke hub 12, and the spring 44 in the bottom cap 13 strives to push thespoke hub 12 upwards, it thus being necessary to push in the steeringwheel rim 9 to the desired level before tightening the locking knob 52.

In FIGS. 2 and 3, the steering wheel 1 is illustrated adjusted to anupper position relative to the steering shaft 2, its lower positionbeing indicated by dash-dotted lines.

A compression spring 55 is fitted between the wedge 45 and the flat slotbottom surface 27 of the spoke hub 12, and said spring strives to pressthe wedge 45 out of the axial slot 20 in the inner hub 11. When thelocking knob 52 is untightened completely, the wedge 45 is howeverprevented from being pushed too far out of the slot 20 by means of anaxial bearing column 42 on the bottom cap 13 which is accommodated inthe recess 18. This also results in that the torque transmission betweenthe spoke hub 12 and the inner hub 11 cannot be disengaged during use orduring an adjustment operation.

The inventive steering wheel hub 8 allows, as previously mentioned,infinitely variable axial adjustment of the steering wheel rim 9, whichis more advantageous than if adjustability were limited to certain givenpositions. In addition, the invention has many practical advantages. Byadjustability being built into the steering wheel hub 8 itself, it ispossible to use the same steering shaft 2 with vehicles which may or maynot be equipped with a height-adjustable steering wheel hub. It is thuspossible to equip already existing vehicles not having aheight-adjustable steering wheel, with an inventive adjustable steeringwheel hub 8. It is also possible to combine the inventive steering wheelhub 8 with means for adjusting the sloping attitude of a steeringwheel 1. It is furthermore simple to adapt the inventive steering wheelhub 8 to a so-called impact-absorbing steering column, used to preventinjury to the driver by the steering wheel in a collision.

The inventive steering wheel hub can be modified into alternativeembodiments within the scope of the following patent claims, and istherefore not limited solely to the described embodiment. Accordingly,the inner hub 11 can be alternatively formed as a hub embracing thespoke hub 12, and the locking means can be formed with stepwiseregulation of the axial height of the steering wheel rim relative to thesteering shaft.

What I claim is:
 1. A steering wheel assembly for a vehicle comprising asteering wheel rim and a steering wheel hub, said steering wheel hubcomprising two telescopically connected, concentric hub parts, of whichan outer hub part is firmly attached to the steering wheel rim via aplurality of spokes, and of which an inner hub part is adapted to berigidly mounted to a steering shaft in the vehicle, said outer hub partbeing connected to said inner hub part via a locking means comprising atransverse wedge, said wedge in a locking position engaging an axialslot in said inner hub part and expanding said inner hub part so thatsaid outer hub part will be fixed to said inner hub part, said wedge ina non-locking position allowing axial adjustment of said outer hub partrelative to said inner hub part.
 2. A steering wheel assembly as claimedin claim 1, wherein said inner hub part is formed with an axialthrough-hole with portions forming shoulders, coacting withcomplementary portions on the upper end of said steering shaft when saidinner hub part is fitted to said steering shaft, thereby to fix saidinner hub part both radially and axially relative to said steeringshaft.
 3. A steering wheel assembly as claimed in claim 2, wherein saidinner hub part is formed with a recess parallel to said through-hole,said axial slot being formed between said recess and an outercircumferential surface of said inner hub part.
 4. A steering wheelassembly as claimed in claim 3, wherein said axial slot in an axiallycentral portion is formed with edge sides sloping toward each other,with the smallest mutual distance at said outer circumferential surfaceof said inner hub part; said slot in an axially upper and in an axiallylower portion, respectively, being formed with parallel edge sides, thedistance between which being greater than that between said sloping edgesides.
 5. A steering wheel assembly as claimed in claim 4, wherein saidouter hub part on its outer circumferential surface has an axiallyextending projection, said projection having on the inside of said outerhub part an open slot having a flat bottom, and on the outside a flatsurface, there being an axial through guiding slot of limited extensionbetween said surfaces.
 6. A steering wheel assembly as claimed in claim5, wherein said transverse wedge is arranged for engaging in saidcentral portion of said axial slot on said inner hub part and in saidinner open slot of said outer hub part, a bolt non-rotatably fitted insaid wedge passing through said guiding slot and on the outside thereofbeing provided with a locking knob which, when being tightened down,acts against said flat surface of said projection.
 7. A steering wheelassembly as claimed in claim 2, wherein a bottom cap is attached to alower end of said inner hub part, a compression spring being fittedbetween an inside of said bottom cap and a shoulder surface formed on alower portion of said outer hub part.
 8. A steering wheel assembly asclaimed in claim 7, wherein said bottom cap is formed with a supportingpillar axially extending into said recess of said inner hub part forlimiting the transverse free movement of said wedge when clamping actionagainst said sloping edge sides in said axial slot of said inner hubpart is released.